Gang Saw Gang Mohammad Jeelani Richard Thrift Barton Pate Michael Knoblett Jeremy Patterson Mark Herndon Justin Owens Joseph Perry Mike Hudgens Problem To design a reliable machine to cut various sizes of scrap wood into survey stakes of specific dimension To reduce labor To maximize production Constraints 1500 Budget 10 x 10 square ft area Compatibility with Indexer Design Size of lumber Gang Saw Layout Input conveyor with board alignment device Gang Saw Assembly Exit Slide Saw Blade and Power Rollers Blades Adjustable for 1 or Cut 1 Stakes for up to 12 Board Width Stakes for up to 6 Board Width Minimum Board Length 12 Feed Rollers Spring Loaded Free Spinning Top Rollers Powered Knurled Bottom Rollers Powered Exit Roller Circular Saw vs Band Saw Low cost of equipment Low cost of maintaining them Low cost of saws High initial cost High cost of saws More susceptible to damage from hard materials embedded in wood Blade Constraints According to Rip Saw Applications we needed to meet a rim speed of 9000 Kerf for carbide tips 15 Teeth must clear wood 8 inch blade for cutting 12 in long pieces Larger the blade the more maintenance Standard Blades Cheap Will not last long Blade tips break easy Diamond Tip Blades Mostly used for cutting steel Diamond is very hard but edge is not as sharp Higher cost Extremely fragile There is a need for an increase of 15 to 30 in power consumption because of the increase in cutting pressure Not using the right power you can run into problems like a Premature edge wear b chipped or broken teeth Carbide Tip Blades Powder like material in its raw state It is shaped by compressing it at high temperatures Increasing the content of carbide wear resistance increases but resistance to shock decreases Harder and more resistant to corrosion Much cheaper Lasts 20 times as long as the standard blade Saw Calculations 8 in R P M 3 8197 Rim Speed Saw Diameter 3 8197 9000 ft m 8 inches 4297 16 Tooth Bite Feed Rate 12 RPM Teeth 16 ft m 12 4297 16 8 0055 Arbor RPM 12 Rim Speed Saw Diameter 3 14 12 9000 8 in 3 14 4299 36 Circumference 3 1416 Diameter 3 1416 8 in 25 13 HP per saw D of C Kerf FPM Factor 144 1 5 15 16ft m 45 144 1 125 Total HP 1 125 7 7 875 Saw Calculations 10 in R P M 3 8197 Rim Speed Saw Diameter 3 8197 9000 ft m 10 inches 3437 73 Tooth Bite Feed Rate 12 RPM Teeth 16 ft m 12 3437 73 10 0055 Arbor RPM 12 Rim Speed Saw Diameter 3 14 12 9000 10 in 3 14 3439 49 Circumference 3 1416 Diameter 3 1416 10 in 31 416 HP per saw D of C Kerf FPM Factor 144 1 5 15 16ft m 45 144 1 125 Total HP 1 125 7 7 875 8 inch Carbide Tip w 8 teeth Cost most suitable for woodworking 12 inch boards would jam machine 8 teeth to carry load out of cut Shaft Design Bending and Torsion 1045 Steel industry recommended Torque on shaft from motor Calculated value of 0 632 inch diameter shaft Shaft Design Cont d Industry experts recommend a diameter of 1 15 16 Inches Compare with calculated value inch shaft selected based on calculations and bearing availability Shaft Selection Keyed vs Splined Keyed Catalog item 1045 Shafts Available Supplier Cheap if purchased Easier to machine Easy to replace Splined Not catalog item Expensive to purchase Difficult to machine Long wait if shaft fails Shaft Prices Keyed 3 4 inch diameter 24 inch length Keyway dim of 3 16 IN X 3 32 in 30 00 Splined Have to be custom made Finding machinist Custom job more expensive Bearing Selection Self aligning for deflection Eccentric lock for one direction of rotation Load and rpm rating Supplier 30 00 per bearing Cost of two 60 00 Major Motor Constraints Single Phase Motor Maximum 15 hp Motor Advantages of the 15 hp motor 15 hp motor results in a feed rate of 30 ft min 2 1 hp 45 15in X 1 5in 144 30 ft min 7 blades x 2 1 hp 15 hp Disadvantages of the 15 hp motor TEFC motor unavailable The Cost of a 15 hp motor is 800 Eliminates the fast feed rate of 30 ft min This eliminates the possibility of a 15 hp Advantages of 2 x 5 hp motors Efficient according to hp calculations Hp per saw 1 5 15 16 45 144 1 13 hp 7 blades x 1 13 hp 8 hp 2 x 5 hp motors are equal to 1 x 10 hp motor Disadvantages of 2 x 5 hp motors The Cost of 2 x 5 hp motors is 974 Hassle as far as one of the motors failing Motors have to be coupled together More space required for the two motors Advantages of 1 x 10 hp motor The Cost is only 650 The motor is the most efficient according to hp calculations Hp per saw 1 5 15 16 45 144 1 13 hp 7 blades x 1 13 hp 8 hp 1 motor is less hassle as coupling and failure are concerned A TEFC motor is available in a 10 hp electric motor Feeder System Gravity Belt Conveyor Chain Conveyor Power Feeder Overhead Conveyor Machined Power Conveyor Feeder Considerations Cost Analysis Final Decision Alignment Mechanism Outlet Ramp Feed Rollers Rough knurled surface to grip the surface of the wood as it is being pushed through the saw blades Chrome coated to prevent wear Mounted just before and after saw blades Driven by sprocket connected to gearbox Smooth roller will be mounted directly above each of the rough rollers 2 inch diameter roller Does not need coating Spring loaded allowing it to be forced up by the board Feed Roller Power Supply Torque Force X Radius Torque 140 lb X 0 0833 ft 11 6 lb ft Horsepower Torque X rpm 5252 hp 11 6 lb ft X 30 rpm 5252 0 066 hp 0 066 hp to force board through saw blades Power supplied from a gearbox connected to main motor Feed Rate 16 ft min or 30 rpm Cost of Purchased Rollers Rough surface Smooth surface 100 150 50 100 At least 4 rollers needed 2 smooth 2 rough Total 300 500 Cost of Chain Feed System 14 inch wide chain made from cast steel with race guide 2500 Must have a forced lubricating system which will cost extra Must have more horsepower to run Cost to Fabricate Rollers 1 stick of cold roll steel 20 feet long 2 inches in diameter 100 or 5 per foot 75 100 for chrome coating Time Blade Spacing Mechanism Requirements of Spacing Mechanism Adjustment of blade spacing 3 4 1 5 Ease of operation Short changeover time 5 min Reliability Low maintenance Low cost Alternatives Babbitt Guide System Set Collars Dual Arbors Compression Springs between blades Pneumatic Actuation Rack and Pinion Human Powered Babbitt Guide System Consideration of Babbitt Guide System Advantages Proven …